The abstract of U.S. Pat. No. 8,443,769 Patent describes its invention in the following language:
This invention relates to internal combustion engines and more particularly to internal combustion engines and methods of operating the engines with a new fuel saving cycle. An engine including at least two piston and cylinder assemblies preferably adjacent to one another, that when operating with the new fuel savings cycle, establish at the end of the simultaneous compression strokes a charge of compressed air in one cylinder of one assembly and a charge of compressed air fuel mixture in the other cylinder of the other assembly. When the air fuel mixture is ignited, the high pressure conditions in the other cylinder are immediately communicated through a passage to the one cylinder to accomplish a double expansion during the simultaneous power drive strokes thus using much of the pressure energy before exhaust occurs by the pistons themselves rather than to dump it as is usually done.